Computer won't power up

[James Richards]

I'm trying to help a friend, she has a HP 733mhz, with Windows ME, about 3yrs old. Twice it has failed to power up, no lights come on or fan or anything, just like it was unplugged. I checked power cord and surge protector, both have power (printer and monitor power lights come on, desk lamp works when plugged in place of computer). The first time it failed , I brought it over to my house to check it out and when I plugged it up it worked. I checked all connections inside and returned it to her. It also worked at her house (plugged in same place as previously). 2 weeks later it failed again, I went over and checked power cord, surge protector, receptacle , everything seems to be ok but PC does not power up (LED does not come on). Brought it over to my house again , it works fine again.
Could this be the power supply and if so, can the 100 watt be replaced by a 250 or 300 watt?
Thanks in advance for any ideas and advice.

[mjc]

IF it weren't an HP I'd say definitely, but HPs use "microATX" pwoer supplies...they are smaller than regular sizedones, so you would have a great deal of troulbe trying to get it mounted. Don't go through HP for a new one, they charge too much. Most online suppliers will carry one that will fit.

[Budfred]

I would wonder if the problem is the power supply or some connection to the power supply or some other weird circumstance. You might want to move it to another location in the same home with a different surge protector and have your friend use it that way for a while to see if the problem persists. If it doesn't, it would suggest that it is some other issue and you don't have to mess with the power supply.

Good luck,
Budfred

[mjc]

Yeah, good ideas, Budfred...I may just get a little carried away (after having 2 PS in my die in 2 years...;) ). I know that HPs have a sort of reputation for cheap PS, that tend to live about a year.

[Budfred]

I really hope that isn't true, I've had mine for well over a year now!!:p

Actually if the thing died on me it would provide more impetus to build my own system, but I would rather do that without having to rely on my 266mhz backup. :D

Good luck on checking out your friends system James.

Budfred

[Sylvander]

Hello James

First, is this one of the newer "Soft Power" systems where the PSU supplies only a minimal power input until the motherboard tells the PSU to start sending all main power supplies through? If so that could be one route to go for an explanation. The motherboard not sending that signal for some reason. I don't know much about the topic.

Second, If its the older, conventional type:
I'll use my diagnostic charts.

SYSTEM TEST
1. Is the PC "dead"? Yes.
2. Does the fan run when you switch on? No.
3. Are power supply voltages correct? I'll assume no. Therefore disconnect all peripherals adaptors and the system board.
4. Does the fan now run when you switch on?
a. If no the power supply is faulty.
b. If yes, then re-connect the system board and:
if the fan no longer runs the system board is faulty,
If the fan does run the system board is not faulty.

5. Re-connect one device and switch on.
If the fan doesn't run this last device is faulty.

6. Repeat step 5 until the faulty device is found or until all devices are connected and the system begins the start-up process.

If it doesn't complete the boot process we can study that separately.